When i put the Jeep in cruise control, after a while at a consist speed it start to surge. for a while I thought it was the road but watching the TACh u can see if bouncing when it happens. if i turn it off and drive fine. any suggestion

 

Welcome to CF! I bet it only does this in overdrive, correct? My wifes' '04 Grand -4.7 w/5-spd auto. does this and we were told it's a problem with OD. Claims is because she never took it out of OD in city driving, or hills. Doesn't do it unless in cruise. In cruise at 72MPH, RPMs surge 500 RPMs every 20 seconds with no corresponding increase in speed. If I disengage OD, it disappears at that speed but RPMs are too high, so I don't use cruise on the high-way.
Driving at 40 engage cruise, it does the same thing. I think it's the cruise control, not the trans. Her Jeep's off warranty, so I can't afford a $2,500 tranny if it doesn't need it.
I hope we find out what this is!

 

VSS maybe